Component driven update method (APSL#251)

Adds an `update` method to allow components the ability to re-scroll to the selected field based on some user-defined event.

Fixes issues that most users are having with auto-growing, resizing, updated or multiline `TextInput` fields.

Examples and Videos description

closes APSL#250

Author: bugs181

lib/KeyboardAwareHOC.js

@@ -30,6 +30,7 @@ export type KeyboardAwareHOCProps = {
   extraScrollHeight?: number,
   keyboardOpeningTime?: number,
   onScroll?: Function,
+  update?: Function,
   contentContainerStyle?: any,
   enableOnAndroid?: boolean,
   innerRef?: Function
@@ -96,6 +97,7 @@ function listenToKeyboardEvents(ScrollableComponent: React$Component) {
       extraScrollHeight: PropTypes.number,
       keyboardOpeningTime: PropTypes.number,
       onScroll: PropTypes.func,
+      update: PropTypes.func,
       contentContainerStyle: PropTypes.any,
       enableOnAndroid: PropTypes.bool,
       innerRef: PropTypes.func
@@ -382,6 +384,19 @@ function listenToKeyboardEvents(ScrollableComponent: React$Component) {
       }
     }
 
+    update = () => {
+      const currentlyFocusedField = TextInput.State.currentlyFocusedField()
+      const responder = this.getScrollResponder()
+
+      if (!currentlyFocusedField || !responder) {
+        return
+      }
+
+      this._scrollToFocusedInputWithNodeHandle(
+        currentlyFocusedField
+      )
+    }
+
     render() {
       const { enableOnAndroid, contentContainerStyle, onScroll } = this.props
       let newContentContainerStyle
@@ -413,6 +428,7 @@ function listenToKeyboardEvents(ScrollableComponent: React$Component) {
           scrollIntoView={this.scrollIntoView}
           resetKeyboardSpace={this._resetKeyboardSpace}
           handleOnScroll={this._handleOnScroll}
+          update={this.update}
           onScroll={Animated.forkEvent(onScroll,this._handleOnScroll)}
         />
       )